1Heat oven to 350°F. Spray 8 (8-oz) individual baking dishes with cooking spray. In 10-inch skillet, heat oil over medium heat. Cook onions in oil 5 minutes, stirring occasionally, until tender.
2In large bowl, mix beans, corn, tomatoes, enchilada sauce and salsa. Stir in chicken, cilantro and onions. Spoon mixture into baking dishes.
3In medium bowl, stir muffin mix, milk and eggs just until moistened. Spoon topping by heaping spoonfuls over chicken mixture.
4Bake uncovered 20 to 25 minutes or until filling is bubbly and topping is golden brown. Sprinkle with cheese blend. Bake 5 minutes longer or until cheese is melted. Garnish with jalapeños.